The use of extracellular lactate as an oxidative substrate in the oxygen-limited frog

摘要: The aim of this paper was to determine the contribution anaerobic respiration metabolism in hibernating frogs exposed progressive hypoxia. Previous studies on acute exposure hypoxia had shown that even at ambient PO2 levels 60 mmHg, cold-submerged were obliged recruit pathways provide enough energy maintain ATP and phosphocreatine concentrations tissues perfectly homeostatic. In current experiments, we hypoxic conditions gradually reveal 30 mmHg probably represents a 'threshold PO2' which survival is still possible, least for 1 week. However, by time threshold reached, liver glycogen reserves exhausted frog must rely thereafter its quantitatively large store skeletal muscle glycogen. lactate produced as by-product glycolytic production did not accumulate but preferentially exported plasma where it held against sizeable extracellular intracellular gradient. results suggest 'shuttled' between poorly-perfused more highly-perfused oxygenated core animal could act both substrate direct oxidation or gluconeogenesis.